1. Field of the Invention
The present invention relates to a video receiving apparatus and a video receiving method, and more particularly, to a technique for receiving a distributed video transmitted via a network.
2. Description of the Related Art
In recent years, development of a video compression technique and popularization of a high-speed network has allowed video distribution services via a network to spread. The video distribution services can be classified into a broadcasting type, a video-on-demand type, and a download type. The video distribution service of the video-on-demand type enables a viewer to select her/his desired contents when she/he wants to view the contents. Thus, the video-on-demand type video distribution service is good in convenience and is expected to be popular in the future.
The video distribution service requires immediacy, so that a real-time transport protocol (RTP) is employed as a distribution protocol, and a user datagram protocol (UDP) is employed as a lower-layer protocol of the RTP.
Since the RTP and the UDP do not have a retransmission function for a transmission error such as a packet loss, an error correction technique referred to as forward error correction (FEC) is employed as an anti-transmission-error measure.
Conventionally, various techniques are discussed for employing the error correction technique. For example, Japanese Patent Application Laid-Open No. 2005-159433 discusses a packet error correction apparatus which controls transmission timing of a retransmission request in occurrence of a packet loss and can reproduce a video and sound at optimum delay time while reducing transmission of an unnecessary retransmission request.
Japanese Patent Application Laid-Open No. 2005-303783 discusses flow control according to a state of a receiving buffer by using a real-time streaming protocol (RTSP) method. Further, a stream reproducing method is discussed in which when an amount of data exceeds an upper limit of the receiving buffer, reproduction is temporarily stopped by PAUSE, and when the amount of data becomes equal to or smaller than a lower limit of the receiving buffer, the reproduction is resumed by PLAY.
However, since the FEC is less effective in a burst packet loss, it is difficult to reliably reduce a disturbance of reproduced video due to a transmission error. In particular, a viewer who purchases pay contents from the video distribution service of the video-on-demand type strongly requires to watch a stable reproduced video which is free from disturbance.